JPH0375775B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a method for determining the traveling direction of a vehicle equipped with a dry single-plate clutch.

(Prior Art) Conventionally, in a vehicle equipped with a dry single-plate clutch, engine braking is used when going down a slope. This engine brake was designed to apply engine braking by engaging the clutch when the rotational speed of the driving wheel side of the clutch was higher than the engine rotational speed, thereby transmitting the rotation of the driving wheel to the engine.

(Problems to be Solved by the Invention) However, since an electromagnetic pickup or the like is used as a sensor for detecting the rotation speed of the drive wheel side of the clutch, it has not been possible to detect the direction of rotation. Therefore, the gear shift direction (forward or reverse) of the forward and reverse gears is opposite to the direction of travel, that is,
The rotation direction of the clutch on the engine side and the rotation direction of the drive wheel side of the clutch may be in opposite directions, and in this case, a force that rotates the engine in the opposite direction is applied to the engine, causing the engine to stall. There was a problem. This is particularly a problem in vehicles with a dry single-plate clutch equipped with an automatic transmission, since the clutch is automatically controlled by the automatic transmission.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a vehicle that can take various measures such as accurately determining the direction of travel and preventing the occurrence of an engine stall.

Structure of the Invention (Means for Solving Problems) In order to achieve the above object, the present invention provides an engine rotation speed detection means for detecting the engine rotation speed, and a drive wheel side of a dry single plate clutch connected to the engine. and a drive wheel side rotation speed detection means for detecting the rotation speed of the clutch, and these rotation speed detection means detect the engine rotation when the rotation speed of the drive wheel side of the clutch is higher than the engine rotation speed when the clutch is in a disengaged state. When the engine speed in the half-engaged state is higher than that in the disengaged state, it is determined that the gear shift direction is Equipped with a dry single-plate clutch that determines that the gear shift direction and the traveling direction are the same, and determines that the gear shift direction and the traveling direction are opposite when the engine speed in the half-engaged state is lower than the engine speed in the disconnected state. The gist of this paper is a method for determining the traveling direction of a vehicle.

(Function) With the above means, the engine rotation speed detection means detects the rotation speed of the engine, the driving wheel side rotation speed detection means detects the rotation speed of the driving wheel side of the clutch, and these two rotation speed detection means detect the rotation speed of the same clutch. Compare the engine speed when the rotation speed of the drive wheel side of the clutch in the disengaged state is higher than the engine speed and the engine speed when the clutch is in the half-engaged state due to the subsequent forward/reverse gear switching operation. When the engine speed in the half-connected state is higher than the engine speed in the disconnected state, it is determined that the gear shift direction and the traveling direction are the same, and the engine speed in the half-connected state is lower than the engine speed in the disconnected state. When this happens, it is determined that the gear shift direction and the traveling direction are opposite.

(Example) An example in which the present invention is embodied in a forklift will be described below with reference to the drawings.

Figure 1 shows the mechanism of the drive system of a forklift.The output of the engine 1 is transmitted to the automatic transmission 3 via a dry single plate clutch 2, and the automatic transmission 3 is used for driving via a differential gear mechanism 4. The driving wheels 5 are moved forward and backward at a predetermined gear ratio. The connected state of the dry single plate clutch 2 is adjusted relative to the stroke amount of the extending rod 6a based on the drive of the clutch control actuator 6. That is, by controlling the stroke amount of the rod 6a, the dry single plate clutch 2 can be disengaged (clutch disengaged state), engaged (clutch engaged state), or half-clutched (clutch half engaged state). .

The automatic transmission 3 changes gears between 1st speed (low speed) and 2nd speed (high speed) by driving the speed change actuator 7, and changes the speed by driving the forward/reverse change actuator 8. The gear position can be switched (shifted) to three positions: forward, neutral, and reverse.

The forward/reverse gear position detector 9 is composed of a plurality of limit switches, and detects the position of the rod 8a of the forward/reverse switching actuator 8 to detect three positions: forward, neutral, and reverse. The transmission gear position detector 10 is composed of a plurality of limit switches, and detects the position of the rod 7a of the transmission switching actuator 7 to detect two positions, 1st speed and 2nd speed.

The vehicle speed sensor 11 detects the rotation of the output shaft 12 of the automatic transmission 3 and outputs a signal proportional to the rotation speed. Further, an input shaft rotation speed sensor 13 serving as drive wheel side rotation speed detection means detects the rotation of the input shaft 14 of the automatic transmission 3 and outputs a signal proportional to the rotation speed. Further, an engine rotation speed sensor 15 serving as engine rotation speed detection means detects the rotation of the engine output shaft 1a and outputs a signal proportional to the rotation speed. These sensors 11, 13, and 15 are all composed of electromagnetic pickups, and cannot determine the direction of rotation, but only output signals proportional to the number of rotations.

Next, the electrical configuration of the forklift configured as described above will be explained.

In FIG. 2, the accelerator opening sensor 16 is composed of a potentiometer and detects the amount of depression of an accelerator pedal 17 provided at the driver's seat. The signal is then converted into a digital signal by an A/D converter 18.

The lever position detector 19 is composed of a plurality of limit switches, and detects the switching state (three positions of forward, neutral, and reverse) of a forward/reverse lever 20 provided at the driver's seat.

A central processing unit (hereinafter referred to as CPU) 21 receives detection signals from each of the detectors and sensors through an input/output interface 22 . CPU2
1 operates based on a control program stored in a program memory 23 consisting of a read-only memory (ROM). Further, the working memory 24 is a readable and rewritable memory (RAM), and is adapted to temporarily store the calculation results of the CPU 21.

The CPU 21 determines the current gear position, such as neutral, of the automatic transmission 3 based on the detection signal from the forward/reverse gear position detector 9, and also determines the current gear position, such as neutral, of the automatic transmission 3 based on the detection signal from the transmission gear position detector 10. The gear position of the automatic transmission 3 is determined.

Further, the CPU 21 determines the current running speed of the forklift based on the detection signal from the vehicle speed sensor 11, and determines the current input shaft speed of the automatic transmission 3 based on the detection signal from the input shaft rotation speed sensor 13. It is designed to calculate the rotation speed of 14. Furthermore, CPU2
1 determines the rotation speed of the output shaft 1a of the engine 1 based on a detection signal from the engine rotation speed sensor 15.

The CPU 21 determines the amount of depression of the accelerator pedal 17 at that time based on the detection signal from the accelerator opening sensor 16 and
Based on the detection signal from 9, the operating position of the forward/reverse lever 20 at that time is determined.

In addition, the CPU 21 has an input/output interface 22.
A control signal is output to the actuator drive circuit 25 via the actuator drive circuit 25 to control the drive of each of the actuators 6 to 8. This drive control is stored in a control program stored in the program memory 23. During driving, the actuator drive circuit 25 is used to shift the automatic transmission 3 to either 1st or 2nd speed depending on the amount of depression of the accelerator pedal 17 relative to the vehicle speed, as shown in FIG. Actuator 7 for changing gears
At the same time, the clutch control actuator 6 is also controlled at the time of this switching.

At the time of this gear change, the CPU 21 determines that the gear has been changed to the target gear based on the detection signal from the speed change gear position detector 10.

The CPU 21 also determines that when the dry single-plate clutch 2 is in a disengaged state, the rotation speed Ni of the drive wheel side of the input shaft rotation speed sensor 13 is equal to the engine rotation speed Ne detected by the engine rotation speed sensor 15.
If the clutch is larger, the direction of travel can be determined by putting clutch 2 in a half-engaged state when engaging the clutch, and comparing the engine speed Ne1 before the half-engaged state with the engine speed Ne2 after the half-engaged state. Determine.

In other words, the CPU 21 calculates the engine speed Ne1 at that time in the disconnected state before the half-connected state.
and the engine rotational speed Ne2 when the clutch is in a half-engaged state due to the subsequent forward/reverse gear switching operation. Then, when the engine speed Ne2 in the half-connected state increases from the engine speed Ne1 in the disconnected state, the CPU 21 determines that the gear shift direction and the traveling direction are the same, and the engine speed Ne2 in the half-connected state increases from the engine speed Ne2 in the disconnected state. When the engine speed is lower than Ne1 at , it is determined that the gear shift direction and the traveling direction are opposite.

Based on this determination, the CPU 21 controls the clutch so that if the gear shift direction and the traveling direction are the same, the clutch is engaged, and if the gear shift direction is the opposite direction, the clutch is disengaged and no switching operation is performed.

These series of traveling direction determination and processing operations by the CPU 21 are performed by a control program stored in the program memory 23.

Next, the forklift F configured as above
The operation when the clutch is switched from coasting will be explained based on FIG. 4.

When the forward/reverse lever 20 is operated in the forward direction (the automatic transmission 3 is set to the forward gear position), the accelerator pedal 17 is depressed to increase the vehicle speed, and then the accelerator pedal 17 is released and the forward/reverse lever 20 is moved. When the vehicle is operated in neutral, the rotational force of the engine 1 is not transmitted to the drive wheels 5, and the vehicle is driven by the inertia force of the vehicle.

Then, when the driver operates the forward/reverse lever 20 from neutral to the forward or reverse side in order to apply engine braking from coasting, the clutch is disengaged and shifted to the forward or reverse gear position, and the clutch is engaged again. When the clutch is engaged, the CPU 21 executes a traveling direction determination routine shown in FIG.

First, the CPU 21 determines whether the accelerator pedal 17 is depressed. At this time, the CPU
21, since the accelerator pedal 17 is not depressed, it is determined whether the vehicle speed is zero (vehicle stopped) or other than zero (vehicle running). When the vehicle speed is other than zero (while driving), the CPU 21 determines whether the forward/reverse lever 20 is operated from the neutral position to the forward or reverse side and the gear of the automatic transmission 3 is shifted to the forward or reverse side. This is determined based on the detection signal from the position detector 9.

When the gear of the automatic transmission 3 is shifted, the CPU 21 detects the clutch drive wheel side rotation speed Ni detected by the input shaft rotation speed sensor 13 and the engine rotation speed determined by the engine rotation speed sensor 15.
Compare with Ne. The CPU 21 controls the clutch control actuator 6 so that the clutch is in a half-engaged state when the rotation speed Ni of the driving wheel side of the clutch is greater than the engine rotation speed Ne.

When the clutch is in the half-engaged state, the CPU 21 compares the engine speed Ne1 in the clutch disengaged state with the engine speed Ne2 at this time.

Then, if the engine speed Ne increases (Ne
1<Ne2), it is determined that the gear shift direction (forward direction or reverse direction) and the traveling direction of the vehicle are the same direction. In other words, the direction of rotation of engine 1 is the same and the number of rotations is greater than the engine speed (Ni>
Ne) on the driving wheel side is transmitted to the engine 1, and the engine rotation speed Ne increases.

Further, when the engine speed Ne decreases (Ne1>Ne2), the CPU 21 determines that the gear shift direction (forward direction or reverse direction) and the traveling direction of the vehicle are opposite. That is, the rotation of the driving wheels in the opposite direction to the rotational direction of the engine 1 is transmitted to the engine 1, and the engine rotational speed Ne decreases.

Then, the CPU 21 connects the clutch (keeps the clutch engaged) when the gear shift direction and the traveling direction match, and disengages the clutch (puts the clutch in the disengaged state) when the gear shift direction and the traveling direction do not match. do).

In this way, the gear shift direction and the traveling direction during coasting can be compared and determined.

Therefore, as shown in Fig. 5, when coasting through a mountain-like road with a series of uphill slopes Su and downhill slopes Sd, the coasting movement goes up the uphill slope Su and crosses the top St. In some cases, the driver tries to coast over the top St, but stops in the middle of the uphill slope and ends up going backwards.

At this time, when the forward/reverse lever 20 is shifted from a neutral state to a forward gear, the gear shift direction is determined, and if the gear is in the opposite direction, the clutch is not engaged, thereby preventing engine stalling.

Note that the present invention is not limited to the above-mentioned embodiment, and the rotation speed of the drive wheel side of the clutch is detected based on the rotation speed of the vehicle speed sensor 11 in addition to the input shaft rotation speed sensor 13. The rotation speed of the clutch on the driving wheel side may be calculated from the switching state (1st speed or 2nd speed). Furthermore, if the gear shift direction and the traveling direction are opposite, various measures can be taken, such as sounding a warning buzzer.

Further, the present invention may be embodied in various other vehicles such as forklifts.

Effects of the Invention As detailed above, the present invention exhibits an excellent effect in that the traveling direction can be reliably determined, and various measures can be taken based on the determination.

[Brief explanation of drawings]

Figure 1 is a mechanical diagram showing the mechanism of the drive system of a forklift that embodies this invention, Figure 2 is an electrical block diagram of the same forklift, and Figure 3 is an automatic transmission that corresponds to vehicle speed and amount of accelerator pedal depression. FIG. 4 is a flowchart for explaining the operation, and FIG. 5 is a diagram showing the running condition of the forklift for explaining the operation. Dry single plate clutch...2, automatic transmission...3,
Travel drive wheel...5, Vehicle speed sensor...11, Input shaft rotation speed sensor...13, Engine speed sensor...15, Forward/forward lever...20, Central processing unit (CPU)...21, Program memory ...23, Working memory...24, Engine speed Ne, Ne1, Ne2, Drive wheel side speed...Ni.

Claims (1)

[Claims] 1 Engine rotation speed detection means for detecting the rotation speed of the engine and drive wheel side rotation speed detection means for detecting the rotation speed on the drive wheel side of a dry single plate clutch connected to the engine are provided, and both rotation speeds can be detected. By the means, the engine rotation speed when the rotation speed of the drive wheel side of the clutch is higher than the engine rotation speed when the clutch is in the disengaged state, and the engine rotation speed when the clutch is in the half-engaged state due to the subsequent forward/reverse gear switching operation. When the engine speed in the half-connected state is higher than the engine speed in the disconnected state, it is determined that the gear shift direction and the direction of travel are the same, and the engine speed in the half-connected state is higher than the engine speed in the disconnected state. A method for determining the direction of travel in a vehicle equipped with a dry single-plate clutch that determines that the gear shift direction and the direction of travel are opposite when the rotation speed is lower than the engine speed.